PROJECT SUMMARY/ABSTRACT Meaningful engagement is a critical dimension of quality of care and quality of life for persons living with dementia. Defined broadly as participation in individual and group activity, engagement has implications for well-being, mental health, and cognitive and physical function and shows promise as a non-pharmacological strategy for addressing anxiety, depression, and behavioral expressions. For residents in assisted living (AL), which is an increasingly popular care setting for persons with dementia, engagement also can prevent or delay relocation to costly and less-preferred nursing home settings, but represents a significant challenge. Although our work shows that most AL residents are embedded in care convoys (i.e. networks) comprised of formal and informal care partners who support their daily activities, opportunities for meaningful engagement are neither universally nor consistently available, especially for those with dementia. Evidence points to the importance of meaningful engagement for persons living with dementia, but also to potential barriers. Despite the significant public health, practice, and policy implications, unknown is what constitutes meaningful engagement and how to best promote it as across dementia type and level of functional ability. The overall goal of this five-year study is to identify best care practices aimed at recognizing, creating, and maintaining optimal meaningful engagement opportunities for persons with dementia that enhance their quality of life. Our specific aims are: 1) To learn what constitutes meaningful engagement in the lives of AL residents with dementia, including how it is perceived and negotiated by care partners; 2) To understand the intersecting factors that promote and constrain meaningful engagement opportunities and experiences in the lives of persons with dementia in AL; and 3) To determine strategies that promote meaningful engagement opportunities and experiences for persons living with dementia. This study will use ethnographic methods, including participant observation, informal and formal interviewing, and record review in 12 AL settings that vary by key individual-, residence-, and local community-level factors, collecting data in three 1-year periods involving 4 sites each. Seventy-five residents with different types of dementia and of varying levels of functional ability and diverse in gender, age, race and ethnicity, and socioeconomic position, will be purposively selected and studied along with the informal and formal care partners. Grounded Theory Method will guide data collection and analysis, which will provide significant insight into residents? meaningful engagement opportunities and experiences, including connections to quality of life. The study will support the National Alzheimer?s Plan and its call to optimize care quality and support persons living with dementia and their care partners by advancing knowledge of engagement, including how to assess its quality in the dementia context, and identifying best care practices that lead to optimal meaningful engagement among persons with dementia.